Plot starter ideas?

I got a bunch of kids who are supposed to travel from place to place. The story starts with two of them, meeting a third and setting out on their journey, meeting the 4th on the way. I've had a lot of problems with this starter and i just cannot figure it out. I'm not going for a super dramatic starter but not a boring one either. I just need something to get them moving. Things to be remembered tho:

1. All children are under 14
2. The action is set in a fantasy world (yes, there's magic in it), with more than half of the world ruled by one mysterious emperor
3. One of them has a history of serious health issues - right now they're fine
4. At one point, one of the characters is suspected to be a legendary being, from a currently extinct specie - no one knows which one tho
   Any idea is welcome YwY

do you have any of the characters mostly fleshed out? figuring out your characters and which two you're beginning with, and which characters are the other two that come along later can be a big help. Also why are they traveling? Are they running away from something or someone, maybe to something?

do you have any of the characters mostly fleshed out? figuring out your characters and which two you're beginning with, and which characters are the other two that come along later can be a big help. Also why are they traveling? Are they running away from something or someone, maybe to something?

All the protags are somewhat fleshed out (especially the first two, the ones that start the story). As for why they travel, that is one of the problems. They are definitely not running away tho

Another question, since this is a fantasy world, is there any magic? What about different races (or species as you mentioned before)? One idea as to why they could be traveling is to find this mysterious emperor for whatever reason, whether it's to fight them or join them. Fighting or taking down the emperor (if they're a bad guy kind of emperor) could be kind of difficult to pull off since the kids are so young. Could they be trying to find something like treasure, for example, Goonies-style? This is one pretty random idea but since the two kids are meeting more along the way, maybe the kid's parents, siblings, or whomever they're close with, have gone missing, and they're dead set on finding them. Whatever way to take this, it sounds super interesting.